The creature that was long proposed as the ancestor of reptiles was the extinct amphibian species Seymouria. However, it then emerged that Seymouria could not be an intermediate form, since reptiles were living on Earth 30 million years before Seymouria first appeared. The oldest Seymouria fossils date back to the Lower Permian stratum of 280 million years ago. Yet Hylonomus, the oldest known reptile species (310 million years old) and Paleothyris (300 million years old) have both been found in Early Pennsylvanian strata, dating back 330 to 315 million years.222

Evolutionists once claimed that the Seymouria fossil above was an intermediate form between amphibians and reptiles. According to this scenario, Seymouria was the primitive ancestor of reptiles. But subsequent fossil discoveries proved that reptiles were living on Earth 30 million years before Seymouria. This meant that evolutionists were forced to withdraw their claims regarding Seymouria.

It is of course impossible for the ancestor of reptiles to have lived long after reptiles themselves.